Multiple position spool valve for machine tools



L. V. HARDING April 24, 1951 MULTIPLE POSITION SPOOL VALVE FOR MACHINETOOLS 7 Sheets-Sheet 1 Filed Oct. 6, 1944 J 3 Al/ 42 I IN VEN TOR. 12 6?flan z 7 L. V. HARDING April 24, 1951 MULTIPLE POSITION SPOOL VALVE FORMACHINE TOOLS 7 Sheets-Sheet 2 Filed Oct. 6, 1944 INVENTOR. 1/2 6;##wrdifi April 24, 1951 v. HARDING MULTIPLE POSITION SPOOL VALVE FORMACHINE TOOLS 7 Sheets-Sheet 3 Filed Oct. 6, 1944 IN VEN TOR.

L. V. HARDING April 24, 195] MULTIPLE POSITION SPOOL VA LVE FOR MACHINETOOLS 7 Sheets-Sheet 4 Filed Oct. 6, 1944 INVENTOR.

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April 24, 1951 v. HARDING MULTIPLE POSITION SPOOL VALVE FOR MACHINETOOLS 7 Sheets-Sheet 5 Filed Oct. 6, 1944 April 24, 1951 L. v. HARDING2,550,148

MULTIPLE POSITION SPOOL VALVE FOR MACHINE TOOLS Filed Oct. 6, 1944 '7Sheets-Sheet 6 INVENTOR. A [0x147 /7 4/'a/ 75. BY

Fig JE.

April 24, 1951 L. v. HARDING 2,550,148

MULTIPLE POSiTION SPOOL VALVE FOR MACHINE TOOLS Filed Oct. 6. 1944 7Sheets-Sheet 7 L4. fPflP/D RETURN Z l 2 QT 49 INVENTOR.

Patent ed Apr. 24, 1 951 UNITED ST ES PATENT OFFICE fiiiin i'rm POSITIONseoonvaiivii roii v d I MACHINE Toots Lloyd 1V. Harding Detroit; Mich;assignor t Le Maire Tooll & .ManufacturingCompany,

Dearborn, Mich, a corporation of Michigan a was; (01. 251-76) Thepresent invention relates to a machinc'e tool and more particularly to aself-contained hydraulically actuated unit in which a mechanicallydriven rotatable spindle is reciprocated relative to a work piece; Suchtools'may'be used to'perform various machine tool operations; such forexample" as single or multiple spindle drilling, reaming, boring, countrboring; spot facing and the like or similar operations. A machine toolembodying thepresent invention is adapted to provide an automaticallycontrolled basic operating cycle which includes'a'rapid approach; feed,"and rapid return of the tool relative to the work piece. The basicoperating 'cycle may; if desired, be modified to provide a dwell afterfeed and prior to the rapid return of the tool spindle. Also, ifdesired, thebasic operating cycle may be readily modified to provide arapid approach, feed, second rapid approach, then second feed, and arapid return, as for example when used: to perform machine operations onspaced parts of a work piece. A principal object, of the presentinvention is to provide a self-contained hydraulically'actu: atedmachine tool in which a power driven rotating spindle is. reciprocatedrelative-to a work piece. by a'plurality of hydraulically actuated ramswhich are. supplied with hydraulic fluid under pressure through 'a novelhydraulic circuit controlled by. automatically actuated hydrauliccontrol valves which determine the operating cycles of the unit.

Another object of thepresent invention is to provide a self-containedhydraulically actuated machine tool in which a power driven rotatingspindle is reciprocated relative to a work piece by hydraulicallyactuatedpower means actuated through a novel hydraulic circuit andcontrolled by adjustable control members for automatically controllingthe operating cycle of the said' tool.

It is a further object of the present invention to provide aself-contained hydraulically actu= ated machine tool which may. beoperated in horizontal, vertical or angular planes and in which amechanically driven rotatablespindle is reciprocated relative to a workpiece by a plurality of hydraulically actuated cylinders connected in anautomatically controlled hydraulic circuit of novel design'to provide a"highly effia cient machine tool of compact construction;'

It is another object of the present invention to provide aself-contained hydraulically actu' ate'd machine toolhaving anautomatically controlled operating cycle including a rapid appreach,feed, and rapid return of thepov ver 2 driven rotatingspindle relativeto a work' piece,

the tool being of a'simplified' and compact design" which is positiveand efiici'ent in'operationand which, when set up, requires'a minimum ofservice and adjustment by the operator.

Other objects of thepresent' invention will 5p;

pear in. thefollowing" description and appended claims; reference beinghad to the accompanying drawings forming a part of this specificationwherein like reference characters designate'corresponding parts in theseveral views.

In the drawings:

Fig. l is. a front elevationpf a' machine tool embodying thepresent'invention looking toward the reciprocating spindle; Fig. 2 is"an elevation with 'partsi broken away showing the right hand side'ofthetool shown in Fig. 1.

Fig. 3 is a vertical section takenfsubstantially on the line 3-3 of Fig.1 looking in the direction of the arrows.

Fig. 4 is a lateralisectio-n" taken substantially mechanism, theviewbeing takenisub'stanti'ally on the line 5-5 01*"Fi'gil' looki'ngin thedirection of the arrows. I

Fig. Gisa sectional view takenalohgthestaggered section line B -B'ofFig: 5 'looking' 'inth'e direction of the arrows.

Figs. 7, 8, '9' and 10 are diagrammatic sectional views showing 'thehydraulic" circuit-actuating cylinder and control val've in theirrespective positions "during the feed, neutral; rapidtappro'ach andrapid return cycles of the spindle respec tively.

Fig. 11 is a wiring diagram showing the 'elec= trical' circuitand"control utilized in a machine tool embodying the present invention.

Before explaining in'detail'jthe present invention, it is to beunderstood that'the' invention is not limited inits application tothe"detai1s0f construction" and arrangement of parts illu's trated inthe accompanying drawings, sincethe invention is capable of otherembodiments and of being practiced or carried outin various ways. Alsoit is to be understood that thephraseology or terminologyemploye'd'herein isfor 'the'purpose of description and notof'limita'tion.

Referringto'Fig's. l and2 of th'e' dravvingfa machine tool embodying thepresent invention comprises a main body casing 20 on"wh'ich the drive"motor 2l"is'mounted. An adjustable" motor mount 22 is pivotallyconnected to the casing 23 by a plurality of pivotal hinge members 23.The adjustable motor mount 22 is raised and lowered relative to the mainbody casing by a motor mount tional speed of the shaft 23 may be varied.The 7 motor mount 25 is sufficient to compensate for the normal range ofvariations in sizes of the sheaves utilized to permit the properadjustment of the motor mount and thus secure proper tension on thedrive belts 25.

A reciprocating tool spindle 33 is moved longitudinally of the machineby a cross-head 3| having connections 32 and 33 with hydraulicallyactuated power cylinders. (Not shown in Figs. 1 and 2 but more fullydisclosed hereinafter.) A generally tangential arm 34 is secured to thecross head 3| and carries a longitudinally reciprocating control shaft35 having control dogs 36, 31, and 38 adjustably mounted forlongitudinal adjustment thereon. The function of the control dogs 33, 37and 38 and of the longitudinal reciprocating control shaft 35 will behereinafter more fully described.

' A manual operating lever 40 for the control valve extends beyond thecontrol valve housing 4| and permits manual operation or adjustment bythe operator of the four-way control valve 42, theconstruction andoperation of which will be hereinafter more fully described.

Electro-magnetic solenoids 53 and 44 are mounted, one on each side ofthe manual operating lever 33 of the four-way control valve 42, and areconnected respectively by links 45 and 46 with the said manual operatinglever 40 to cause the lever to pivot about the pivot point 38. Movementof the manual operating lever 45, either manually or by actuation of thesolenoids 43 or M, is

transmitted to an integral valve spool operating.

fork 39. The lever 55 and the operating fork 49 thus constitute arotatable crank arm.

A manual cycle start button 50 and limit switches and 52 are mounted onthe side of the casing 20.

An oil pressure gauge 53 is suitably connected with a cut-off valve 54and a conduit 55 with the oil pressure system inside the unit and showsthe operator instantly the pressures on the hydraulic fluid.

A flow control valve adjusting member 55 and a relief valve adjustingmember 5'! are provided outside the casing 20 to permit ready adjustmentof the respective valve members from outside the casing 20 by theoperator if and when required.

Figs. 3 and 4 show the interior of the casing 23 and illustrate themechanism for rotating and reciprocating the spindle 35. As here shown,the casing 28 encloses a gear chamber 60 to which access may be hadthrough a removable gear chamber cover (H. The gear chamber 33 isseparated from the hydraulic sump chamber 52 by an in-' ternal web 63integral with the casing 66.

The machine drive shaft 29 is journaled in bearings 65 mounted in theremovable gear chamber'cover GI, and in bearings 65 which are carried.by-the internal web 63.

V, Aconstant volume hydraulic pressure pump 31 of any suitable designand construction is mounted on the web 63 and extends into the hydraulicsump chamber 62. The drive shaft 68 of the pump 61 is keyed into arecess 59 in the end of the machine drive shaft 29 as shown.

The machine drive shaft 29 is provided with a shoulder 10 against whichabuts one face of a main drive gear TI. The main drive gear 'H issplined on the shaft 69 and is removably maintained thereon by a gearmounting nut 12 and a gear mounting washer l3.

The teeth of the main drive gear Tl mesh with the teeth of the spindledrive gear 14 which is splined on a female splined spindle drive housing.15 which is rotatably journaled in bearings 16 and r 11 carried by aportion of the web 63. An oil seal 18 extends around the housing 15 andprevents leakage of hydraulic fluid from the sump chamber 62 into thegear chamber 60. The gear chamber 60 is filled with any suitable gradeof gear lubricant and this also is prevented by the oil seal fromseeping into the hydraulic fluid sump 62. The relative speed of themachine drive shaft 29 and the oil pump 6'! and of the spindle 35 arecontrolled by the gear ratios of the gears H and I4. Both gears arereadily accessible when the removable gear housing cover 6| is removed.A cap 83 and a gear nut 8l may be removed from the end of the splinedhousing 15 to permit ready removal of the gear 14. By substitutingvarious gears for the gears TI and 14, any desired gear ratio may beprovided;

The spindle 30 is mounted on a spindle drive shaft 82 which is journaledin'bearings 33 and 84 carried in the reciprocating spindle housing 85.The spindle drive shaft 82 is provided with a male splined end 83 whichtelescopes within the female splined portion of the spline member 75.Bearing take-up adjustment nuts Si, 88 are screw threaded on the shaft82 and prevent end play of the bearings 83 and 84 respectively. Abearing take-up adjustment nut 89 is screw threaded on the spline memberand prevents end play of the bearing IT.

The reciprocating spindle housing is mounted in a spindle housing guide90 formed integrally inside the casing 25. An oil seal packing 9| isheld in a recess 92 in the housing 20 and is maintained in fluid tightrelation therein by a removable plate 93 having an oil seal packingflange 94. This construction prevents leakage of hydraulic fluid throughthe casing 20 from the hydraulic sump 62 upon reciprocation of thespindle housing 85.

The reciprocating spindle housing 85 is provided with an enlarged head95 to which the cross-head 3| is secured. An oil seal 93 surrounds thespindle 30 and is carried in the crosshead 31 to prevent the seepage ofoil through the bearings 84.

The spindle 31! here shown is a standard Morse taper spindle but it isto be understood that any other suitable type of spindle may be used ifdesired. For example, such a spindle may be replaced by a spindle suchas that shown in Fig. 2 and indicated by the numeral 91, which is thetype of spindle recommended when a machine tool of the present inventionis intended for use with multiple drill heads. In either instance asuitable tool holder or tool holders (not shown) are to be employed withthe spindle here shown. Since such tool holders are of conventionaldesign and construction they are, for the sake of clarity omittedfromthe drawings herein,

Hydraulic power to effect reciprocation of the .ts hd ez 3 h s-applie tqiheacrossrhea 3 han t mi tedt rpueh i ,lng J chatter and vibration ofthe spindle 30 and the housing 35 gluring the reciprocating movementthereof are eliminated by providing a plurality V; of hydraulic pressureoylinders, in the present inst tw con ehte t h .-@r i :hee a p ts. 32 nnfi o theqhnqshaeid of h pindle. 13h i td ll hd r o d ev ha any desired,number greater than; two V of such =y1.i,. de. ma 1 9 ed i d sire I asuch ca se a plurality .of cylinders vvill be con- I he ted a a uralitoi po nts r e a l s ac uequa lyabo t th i hmfe ehq o the r n e Thehydraulic pressure cylinders here 1 shown in the main housing 20. Thecylinder chambers are provided respectively with inlet ports I 02 and aehhah tehrhliiah 0 a permit the .ofhydraulic fluid to and fronith'ecylinder ing was Insane osfha'vin'g their other ends connected to thecross-head 3! at the points-32 andi-ifi respectively. While anypreferred sizes may be "employed; the connecting rods I08 andiflllhereshovvn each haveadianieter of approxiniatel'y onevhalfthatofthe piston to which they are connected. This effects a reduction ofapproximately. fifty per cent in the fluid capacities fjthat'port'ion ofthe cylinder chamber through which the'r'ods pass. In other Words,the'fiuid capacity of the cylinder chamber betweenthe intake ports' andthe heads of the pistons isap proximately twicethej'fluid capacity ofthe chamfherlbetween the exhaustlports and the skirt of the pistons.Bysuitalolefchanges in the X diamv eters of theconnecting'frods,the'ratio of fluid "capacity in thetwoparts' of the cylinderchambersm'ay. be varied as. desired. T

The exhaust endsof the cylinder chambers ji 00 and l0'l' are closedbyfcaps H0 and i l l, respectively. Oil seals H2 and H3 areretained inthe caps Hiiand iii, respectively, and contact the sides of theconnecting rods I08 and l09,respectively," to prevent seepage ofhydraulic fluid; around the said rods during the reciprocation thereofRemovable packing flange members H4 and H5 are mounted on-the baseportion of the main casing 20 and contact the oilseals' I I2 and H3,respectively. i -{Ihecon1p1ete operating cycle of the tool here shown.consists of a reciprocal movement of the o rotating spindle from aneutral position to provide a rapid approach stroke, a ieed'stroke and arapid return sjtroketo theneutr al position. It is intended that a toolof the present invention will operate automatically throughout thecycle,

but if desired,as ior example on special Work, or

When there has been afailure of the automatic control mechanism, themachine may be controlled throughout the various phases of its operatingcycleby manual adjustment of the four-Way control valve 42 by the manualcontrol lever 40.;The reciprocation Otthespindle 30 through its.operating cycle is controlled by the hydraulic circuit, controlvalve-and electrical con.

,trolmechanism shown inFfigs, 5 to 11, inclusive.

' Referring toEigs. 5 and 6,,th llQQl1 tiiuction and .op'eration of thefour vvay control yalve 42 is om ris l nde c ambe s a ii; iforhid 1 "cam31 carried on the shaft- 35.

a reciprocating spool 120,. movable in a valve chamber or manifold 12!,and having ports communicating respectivelyvvith the pum 51,

themes her in: andwmne exhau tpp i 1M and I05, and the cylinder chambersand i0],

and with the sump 62, as Willbe more f ully'de- 'Ehe is lo m si n hdedja 1 en wit a camj f aced head j 22 adapted to be contacted by a Atthe other scribed in connection with Figs. 7 to 10, inclusive.

end, the spool I is provided with el-sgr eveL .;Whi is hge e r vaiglhrhhty .of spring pressed ball check members 124 upon movementofthe'spool "I 20 to its neutral. position;

=-'Ihis assures v accurate .seati'ngoof the a spool I20 inhthe neutralposition and prevents any possible longitudinal movement of the toolspindle while the parts are in the neutral position.

' The hydraulic circuitin thevarious positions of the spool I20 to;efieotrespectively the feed, neutral, rapid approach and rapid return.opera- 1 tions of the spindle is shown diagrammatically inl igs. 7 to10. inclusive.

* Feed cycle The feed cycle shown in-'Fi g.'-7 utilizes the entirehydraulic circuit which includes in addition to theparts-.previous1ydescribed, a relief valve I25 which is adjusted from;outside thecasing zfl by theadjustmentshaft--51, and a metering flow Icontrol valve [26,- vihichisadjusted from outside the casing20 by theflow control adjustment member 56. :flhe relief valve I25 is of aconventionalspringloaded type and the metering fiow V control valve 126isof a conventional metering orifice type. Since-both the valves l 25and 126 are welllgnownconventional constructions, they arenothereshownor describedin detail.

As shownjoy the arrows in Fig.7, when the spool' lzfl'is moved t o itsfeed position as there shown, "by contactof the feed cam 3? with'the l al'ia e hea L2 o t $09 12 .ihhhrfdraulictpressure fluid is withdrawnfromthe ,SumpYGZ by'the pumptl; and passes through the ports: of .thevalve"manifold I2! and around the spool l20 fito the hydraulic feed line 130,supplyi the ihtah ro t 102 and 1 of e l de chambers 1.00 and 1.0!. Dueto the relatively re-' Q'stricted amount of hydraulic fluid requiredduring'the feedoperation, the pressures created in the hydraulic" fluidvrnove the spool l3l of the spring pressed relief valve 125 and theexcess hydraulic feed fluid is by-passed directly through thereliefvalve['25 tothe sump 62. As the pistons I 061an'd [01; are moved inthedirection of the arrows, the hydraulic fluid from the exhaust po rts-I04 and I05fl0ws through the exhaust line I32" and through the manifoldl2] and around the -s'pool I'20 and is discharged through a line 133leading to the metering flow control valve I fI fhe rate of speedtherethrough is determined by the adjustment of the metering flow"controlvalye 126 which determines how rapidly V the exhaust i luidisreturned through the .dis-

chargeconduit iei to the-sump 62, and consequently thepamountfofbackpressurein the cylin e c a be s sin ihj m vem of t pis on [0 amlliihethii a 'circumfervolumes. By providing a three volumes thus portsI04 and I05 by Neutral position When the spool I20 is moved to theneutral position as shown in Fig. 8, the spring pressed ball I24 drops'into the circumferential groove I23 and holds the spool I20 againstunintended movement. When in this position, the entire flow of hydraulicfluid is by-passed to the sump -62 as indicated by the arrows. In thenormal cycle, the turn cycle and precedes the rapid approach cycle. If adwell is desired in the operating cycle, a suitable control member maybe provided to move the spool into neutral position immediatelyfollowing the feed cycle and immediately preceding the rapid returncycle.

Y Rapid approach and rapid return cycle neutral position follows therapid reof the machine tool by cutting down the time interval requiredfor movement of the reciprocating tool spindle 30 to and from the feedposition, When the spool I20 is moved to the position shown in Fig. 9,the rapid approach cycle is established. Due to the fact that the pump61 is a constant volume, constant feed pump, if its size is selected asadequate for all other needs of the operating cycle, it does not pass asufficient volume of fluid to effect the rapid advance. In previousconstructions attempts have been made to supply sumcient fluid to effecta rapid advance of the spindle either by increasing the capacity of thepump 61, as by using over-sized pumps, or by providing a variablecapacity pump. Such expedients increase the cost of the pump or increasethe size of the entire machine and have not been wholly satisfactory. Tosupply the required volume of hydraulic pressure fluid in the given timeinterval to effect the rapid approach, hydraulic pressure fluid from theexhaust ports I04 and I05 passes through the exhaust fluid conduit I32and through the valve manifold I25, and around the spool I20, to thefeed duct line I30. To illustrate this operation, by way of example, ifit is assumed that each of the cylinders I00 and IOI requires one volumeof fluid during the feed cycle, a pump of suflicient capacity to handlethe feed cycle would have a total volume of two. To effect the rapidapproach it may be assumed that each cylinder would require one andone-half volumes of fluid or a total of three pump having a capacity oftwo, which is sufficient for the feed cycle, it will be seen that thepump would be of insufficient capacity to provide the required threevolumesfor the rapid approach cycle. Since each connecting rod I08 andI09, is in the present instance, approximately one-half the diameter ofthe piston to which it is connected, the capacity of the cylinderchamber through which such rod passes is reduced by approximatelyone-half. Therefore, by passing one-half volume of fluid from theexhaust end ofeach cylinder to the feed endsthereof, there are provideda total of three volumes of hydraulic fluid under pressure. The madeavailable are sufficient to carry out the rapid approach cycle withoutrequiring an increase in size or the capacity of the pump. Since thefluid is discharged from the the pressure induced movement of thepistons I06 and I01, the discharge fluid is under pressure and this,when combined with the pressure fluids from the pump 61, augments theavailable supply of pressure fluid and increases the amount of pressurefluid available at a given time to carry out the rapid approach cyc e.

In the rapid return cycle as shown in Fig. 10, the spool I20 is moved tothe position shown in which the entire volume of hydraulic pressurefluid from the pump 61 is supplied to the conduit I32 and is fed intothe cylinder chambers I00 and MI through the exhaust ports I04 and I05.Since the volume of each of these chambers is reduced by approximatelyone-half by the connecting rods I08 and I09, there is available asuflicient volume of hydraulic pressure fluid from the pump 61 to effectthe rapid return of the spindle. The excess fluid on the opposite sidesof the pistons is discharged through the conduit I30 and the valvechamber I2I to the sump 62.

in its operation through the electrical circuit shown diagrammaticallyin Fig. 11 and which includes the cycle start switch 50, the limitswitches 5| and 52, and the valve solenoids 43 and 44. The motor 2I isconnected through over-load relays I40 and over-load fuses I4 I, with anelectrical power source. The control mechanism is supplied withelectrical energy from the motor supplying circuit through a controltransformer I42 which is connected with fuses I43 and with the motorstart switch I44, and a motor stop switch I45.

A normally open relay switch I46 is connected in parallel with the motorstart switch I44 and is closed by energizing the holding coil I41, whichalso energizes the normally open relay switches MBA in the circuit forthe motor 2I. Over-load relays I48 and I49 are connected in series withthe motor stop switch I and the holding coil I41.

The cycle start switch 50 and the motor start switch I44 and motor stopswitch I45 are manually actuated. The limit switches 5| and 52 areactuated by the control dogs 36 and 38 respectively, carried on thecontrol shaft 35. The electric circuit as shown is such that the limitswitch 5I must be closed, as shown, through the circuit including switch50 and coil 43 before closing the cycle start switch 50 will beeffective. The limit switch 5I is closed (moved to its upper position inFig. 11) by the conrol dog 36 when the spindle is retracted and themachine is in the neutral position. In this position, actuation of thecycle start switch 50 actuates the solenoid 43 to move the spool I20into the rapid approach position shown in Fig. 9. If the limit switch 5Iis not closed by the dog 36 upon the complete retraction of the spindle,the rapid approach cycle cannot be established. This is an importantfactor since it prevents unintended establishment of the rapid approachcycle such as might otherwise occur. If for example, the spindle was inthe feed position when the cycle start switch 50 is actuated and therapid advance cycle was thus established the machine would causeexcessive tool breakage or wear due to excessive feed pressures or thepressures might be such that the machine would be stalled. By thisprovision, the cycle start switch is rendered inoperative until thespindle is fully retracted and the parts occupy their neutral positionsshown in Fig. 8.

Upon actuation of the cycle start switch 50, the

' aslsn'ownfirr FigJlQ lands provided w w fi mhe v tior 'arygomplartments, numbere '5 appjrbaii position as th'hydraulically'actuated"andfcontinus nti adizz q I 1gp 'nt th" re dosition'sho inrig, 7. As

a theldos p I se rides Iofif the limit switch 5|, the latter pivots, Ho'its downward position, as indioa'tedfbyjth'e arrow. inf Fig, 11, toclose the circult, between the now closed'relay switch I46 andthejjopenfllimit swit'chBZ, The coil 43.15 thus de-. energized'almos'timmediately after the spool I mOvestdjthe rapid approach position, butthis in no way alters the position of the spool Hill 7 'I'h e' 'spoollZll isheld' in the 'feedposition' for a mode lfiniine'dftime interval'until the dog 33 on 35 closesthe limit switch 572, completing itchl'46,' switjh 5 lin the the' solenoid 44 which latter 0 to 1 its rapidreturn position v 'I 'h emanually operated restrokelswitchf 52A iSprovided in parallel the spool, l2

.with thejlimit'fswitch -52 to permit the return strok 'to wbe actuatedat anytime that the dog 36 is hot'holding the'fswi'toh' 5| in"the'raised positionfshown inQFig 11.j r g p 7 From the! foregoing itwill -be seen that a. inachine tooljof novel v operating characteristicshas been provided and which may, beoperated either or; by manual operandthe control valve automatiogallyias. described" vconhetiongwithl the],motor so.

at; a predetermined contact.

of the spmcue isj effeoted by lth'e, hydraulic cylini dersj and is",

flcontrol mechanismQa ,lfourv 7 position compartrnentalvalve having twomating recessed valve elements selectively movable. reciprocallyrelative to'each other,'a plurality of byleaohTof. said; elements andDartitioni ngsaid rec essesiinto a plurality of compartrnents spacedsideby side in the direction of the relative, reciprooal mqvement. of saidtwo elements, six ports; 0n'e' of"'eac'h communicating v with one ofeach of six ofsaid compartmentsan'd including two inlet ports, two"discharge port's;

v v andt'wo operating ports, said compartmentsbe irig selectivelyinterconnected by'relative move-q Y ofs'aid-elements-to connectone ofsaidi'n 'let'portswithboth of said operating ports; onto cofihect'either of said operating'ports with one ofsaid inleti-ports andsimultaneously ltoi coflfthf'othl" operating port with oneofsai ddischarge portslorto pon'n'ec't'oneof saidinletf;

withone of said discharge ports while si miiltaneousl'y closing each ofsaidoperating ports froinf any other ports, said fir'stvalve element isst nary and is partitioned intofsix stationary co artm ts by fivestationary lands, saidsia ,po Q nn 'cate with said stationary com andfourth h W ;Qoonsec utive 1y, being saga two inlet ports; the second andsixth ports to the thei 1 on theishaftficontacts the; cam facedffthelspool j! 29, and m'o'veslthe spool Thefreciprocating'j' transverseimovern'ent,

LjThe ap'id approachf strokeis. V

compartmentabuts the second so as to isolate each of the firststationary land v first moving land lies between the edges of the thirdstationary compartment to permit communication between the third andfourth stationary compartments; the outer edge 7 .vof the 'second movingland abuts the fifth sta-' tionary land so as to isolatethe sixthstationary v compartment from the other stationary com-'1 partments andthe other edge of the second moving la'nd lies between the edges orthefifth l stationary compartment to permit communicatio between thefourth and fifth stationary 'com partments; in the second position ofsaid valve; theifirst moving landabuts the first; stationary land andisolates the first stationary compart- ,ment from the other stationaryoompartment's,

"the secondary stationary land lies between the edges of the secondjmoving compartment to permit communication between the'seoond an'd thirdstationary compartments, the second moving Mlandabuts the thirdstationary land so as to prevent communication between the third andfourth stationary compartmentsythdthird mov dle tfl'is at, all timesdriven a ing compartment extends on'leither 'side beyond the e'dges ofthe fourthstationary land topermit communication' between the fourth andfifth r stationary compartments, and the outer edge of l the thirdmovingcompartment lies between the. edges of 'thefifthstationary'compartment'so as to isolate the sixth-stationary compartment from all"the fother stationary compartments;- in the I municatiorib'etweenthefifth and sixth stationthirdposition o'f 'thevalve; the outer edge ofthe;

first moving compartment liesiibet'ween the edges of the secondstationary compartment so as tol "isolate the firststationarycompartment from all r the other stationary compartments; the first:'moving 'land abuts the second'stationary land andisolates the secondstationary oompartment from all the otherstationary'compartmentsyoneedgeof the second moving land abuts the fourth stationary land so as toseparate the'fourth and 'fifth compartments from each other, and thefifth stationary landlies between the edges of the third movingcompartment to permit comary compartments; and in the fourth position*ot the'valve, the first stationary land 1iesbe;-" tween the edges ofthe first moving compart ment to permit-communication between the firstarid second stationary compartments; fthefirst movingland'abuts' theedges of the second stai-i tiOnary land to separate the'second and thirdstationary 'e'ompartments from eaclrother, l the second moving landabuts both'the third and fan and sixth stationary erp a 2, In ahydrauliccontrol adapted to operate a; reciprocating'dififerential areahydraulically ao fourth stationary lands so as to closethe'fourthstationary 'ompartment from the otherstationare "compartment; and theouteriedgeof the third moving compartment; abuts the fifth stationary'land 'so s to separate each of the-fifth compartments frome'achm p ston. m eiw i ii ari en nders l itrolili is fl Pres re; u c and a u.sumaan ellva e c mpr in *a Valve eylinderanda spool axially slidablethere- V so porttitheft ira andflfifthfports, being said twooperatinglports; the second valve element is reciprocally'movable and isj partitioned into three ments by two moving lands; in the firstposition of saidvalve the outer edge of the first moving movingcompartand second sta- ,tionary oompartments from the other stationary jom arime t h in, said valve cylinder having a plurality of axiallyspaced fiuid ports including a first inlet port adapted for connectionwith the fluid pressure source, a first outlet port adapted forconnection with the sump, a first feed duct port adapted for connectionwith the piston cylinder at the end having the larger piston area, asecond inlet port adapted for connection with the fluid pressure source,a second feed duct port adapted for connection with the opposite end ofthe piston cylinder and a second outlet port adapted for connection withthe sump, said ports being positioned in the order named, and said spoolhaving four axially spaced land portions to control fiuid communicationbetween said ports, said spool being movable within said valve cylinderto a rapid feed position wherein the first of said land portions closessaid first inlet and said first outlet ports and the third land portioncloses said second outlet port and wherein said land portions permitfluid communication between both of said feed duct ports and said secondinlet port, said spool also being movable within said valve cylinder toaslow feed position wherein said first land portion closes said firstinlet port, said second land portion closes communication between saidfirst outlet port and said first feed duct port and said third landportion closes communication between said second inlet port and saidsecond feed duct port and whereby said land portions permitcommunication between said second inlet port and said first-feed ductport and between said second feed duct port and said second outlet port,said spool also being movable within said valve cylinder to a neutralposition wherein said second land portion closes communication be-'tween said first feed duct port and said first outlet port, said thirdland portion closing communication between said first feed duct por-t,said.

second inlet port and said second feed duct port and said fourth landportion closing communica: tion between said second feed duct port andsaid second outlet port, and wherein said land portions permitcommunication between said first inlet port and said first outlet port,said spool also being movable to a rapid return position wherein saidsecond land portion closes communication between said first inlet portand said first outlet port, said third land portion closes communicationbetween said second inlet port and said first feed duct port and saidfourth land portion close communication between said second feed ductport and said second outlet port and wherein said land portions permitcommunication between said first outlet port and said first feed ductport and also between said second inlet port and said second feed ductport.

3., In a hydraulic control adapted to operate a reciprocatingdifferential area hydraulically actuated piston movable within a pistoncylinder and including a constant volume fiuid pressure source and afiuid sump, a novel valve compris ing a valve cylinder and a spoolaxially slida'ole therein, said valve cylinder having a plurality ofaxially spaced fiuid ports includingfafirst inlet port adapted forconnection with the fiuid pressure source, a first outlet port adaptedfor connection with the sump, a first feed duct port adapted forconnection with the piston cylinder at the end having the larger pistonarea, a second inlet port adapted for connection with the fluid pressuresource, a second feed duct port adapted for connection. with theopposite end of the piston cylinder and a second outlet port adapted'forconnection with the sump, said ports being posi- 12 tioned in the ordernamed, said cylinder also having land portions between each of saidports, and said spool having four axially spaced land portionscooperating with the land portions of said valve cylinder to controlfluid communication between said ports, said spool being movable withinsaid valve cylinder to a rapid feed position wherein the first of saidspool land portions closes said first inlet and said first outlet portsand the third land portion closes said second outlet port and whereinsaid spool land portions permit fiuid communication between both of saidfeed duct ports and said second inlet port, said spool also beingmovable within said valve cylinder to a slow feed position wherein saidfirst spool land portion closes said first inlet port, said second spoolland portion closes communication between said first outlet port andsaid first feed duct port and said third spool land portion closescommunication between said second inlet port and said second feed ductport and whereby said spool land portions permit communication betweensaid second inlet port and said first feed duct port and between saidsecond feed duct port and said first outlet port, said spool also beingmovable to a rapid return position wherein said second spool landportion closes communication between said first inlet port and saidfirst outlet port, said third spool land portion closes communicationbetween said second inlet port and said first .feed duct port and saidfourth spool land portion closes.

communication between said second feed duct port and said second 'outletport and wherein said spool land portions permit communication betweensaid first outlet port and said first feed duct port and also betweensaid second inlet port and said second feed duct port.

LLOYD V. HARDING.

REFERENCES CITED The following references are of record in the file ofthis patent:

- UNITED STATES PATENTS Number Name Date 1,147,820 Scott -1 July 27,1915 1,787,781 Galloway Jan. 6, 1931 1,909,166 Burrell May 16,19331,999,248 .Melling Apr; 20, 1935 2,016,654 Shippy et a1. 'Oct. 8, 19352,036,162 Svenson Mar. 31, 1936 2,051,052 Morgan Aug. 18, 1936 2,111,689West Mar. 22, 1938 2,160,217 Kingsbury May 30, 1939 2,167,106 Dunham eta1 July 25, 1939 2,180,817 Nye Nov. 21, 1939 2,274,603 Herman et al Feb.24, 1942 2,307,544 Robinson Jan. 5, 1943 2,309,983 Riddle Feb. 2, 19432,310,124 Shartle Feb. 2, 1943 2,324,727 Shartle July 20, 1943 2,328,311Vickers Aug. 31, 1943 2,365,748

Curtis Dec. 26, 1944

